Vortex-type gas burner



July 11, 1950 R. D. SHAPTER 2,514,806

VORTEX-TYPE GAS BURNER Filed June 15, 1945 2 Sheets-Sheet 1 July 11, 1950 R. D. SHAPTER 2,514,805

' VORTEX-TYPE GAS BURNER Filed June 15, 19 45 2 Sheets-Sheet 2 Fl -'4 FIG-5 Patented July 11,1950, 7 Y r 2,514,806

vciriixfl alridf prdrsss; puflwaril thg ir'iner xixigils of the :ijrrilqi siiion ti lbe gr protect ed irom m flame temperature lpy a blanket 9 air.- .Thl n r ll f e of tion alpng the cor'hbiistionitub in the; heating of phe be' ,in which err red; z'qns} of maximum 7 temperature 5i plral'eid sliding theicombulstioniuh. Thg pitch of the spirai i. 1,, the axial progression t ul'o per; Evolution of the air starts at the widthrof the riqzzle A, and gradas the air progresses alcmg the .Q f 'jajlk v v i i r, or more strictly speaking, the'fuel y} a 1101; wire cqil fl l mounted or! a. m c a 12in" 2; chambgr l3 at} the; outer I v ,Eh i u rim' c d Qhamh n co iatifig therewith through a j na rrow slqt I 4. {Ijheslqt is ubehin d a, plate ifi whih shields lthe fromit em i ifiihe c m usr riitidr coil ll isjhated t9 inpam Qre Ug e},jfue1 suppiy is hurr ed 01 1, wi er jfthqfuel .supply.is turned on, th 151 191 difiu iritp the ignition pha rnber, I3 through 4, am; is ignited" by" "cd nt acL with the 11;, I] The, ignited mixture expands 16:1 have b the blower and the nozzle 4 to heat the combustion air and thereby heat the thermal element. When heated the thermal element opens the contact I and closes contact IS in the circuit of a normally closed Solenoid valve in the gas fuel line. As soon as combustion starts the heat of combustion radiates to the thermal element l6 and keeps it heated so as to maintain the contact l9 closed. If the combustion stops for any reason, the thermal element is cooled by the combustion air and the contact H3 is opened and the contact I'I closed.

The fuel supply will also be cut off if the power supply is interrupted, de-energizing the solenoid valve 20. Even for a momentary interruption it is desirable that the burner be shut down and restarted since the temperature in the combustion tube may be insufiicient to ignite the fuel. This is accomplished by interposing a time delay be-:.

tween the closing and reopening of the solenoid valve 20. In the present construction the thermal element l6 is utilized for providing the time delay through a relay 2| energized through the contact closed only when the thermal element I6 is cool so that if the power supply is interrupted the relay 2| can be energized only after the thermal element has cooled. The relay 2| when energized closes normally open contacts 22 in thecircuit of the solenoid valve 20. The opening of the contact I! upon operation of the thermal element l6 deenergizes the relay 2| but its contacts 22 do not open until after the contact I9 has been closed and the solenoid valve energized. The solenoid valve has contacts 23 in a holding circuit 24 which keep it energized after the contacts 22 are opened. Upon power failure while the burner is operating, the contacts 23 open and since the contacts 22 are open, energizing of the solenoid valve is not possible until the relay 2| has been energized through the contact IT. This can only take place when the thermal element |6 has cooled. It is therefore im- .possible to supply raw fuel to the burner except when combustion is taking place or until the ignition circuit has been energized by the closing of the contact The burner is controlled by a switch 25 in the power line 26. Closing the switch 25 energizes the combustion air motor 6 through contacts 21 of a thermal overload protecting device 28. The contacts 21 are closed during normal operation and open when the motor is overloaded, for example, by bearing failure which would reduce the speed so that an adequate supply of combustion air would not be furnished. Other motor protective devices may be used. The ignition coil II is fed through the combustion motor circuit through the contact IT. The ignition coil cannot be turned on unless the combustion motor is operating normally since under abnormal operation of the combustion motor the protective contacts 21 will be opened. The contact I! controls the circuit to the heating element l8 and to the relay 2|. The relay 2| picks up instantaneously and closes the contacts 22 in the circuit of the solenoid valve 20. The heating element l8 causes the opening of the contact I! and the closing of the contact IS in the circuit of the solenoid valve 20.

From one aspect the thermal element l6 and the relay 2| constitute a time delay relay interposed between the circuit 20 to provide for a time delay between the turning on of the ignition coil and the opening of the fuel supply. This time delay insures the heating of the ignition 4. coil to the proper temperature before the fuel supply is turned on.

It will be noted that the control system is arranged so that failure of any of the elements shuts down the burner. Failure of the combustion air motor 6 causes the opening of the protective contacts 21. Failure of the ignition coil ll opens the circuit to the heating element I8 and prevents energizing the solenoid valve 20. Failure of the heating element It! prevents the heating of the thermal element IE to close the contact is in the solenoid valve circuit. Upon momentary failure of the power supply or upon opening of over temperature control contacts 29, the relay 2| opens the contacts 22 and the solenoid valve -20,closes, opening its holding contacts 23. The circuit to the solenoid valve cannot be reestablished until the thermal element 16 has cooled suificiently to close the contact II.

The control diagram of Fig. 5 is similar in operation to the control diagram of Fig. 4. and corresponding parts are indicated by the same reference numerals. The principal difference in Fig. 5 is the substitution of a relay 2| a for the relay 2| which controls contacts 22a in the circuit of the solenoid valve and also controls contacts 23a in a holding circuit 24a. In effect the holding circuit has been taken off the solenoid valve and placed on. the relay. The relay is energized through a contact l'la closed by the thermal element |6 concurrently with the contact H. The purpose of the additional contact is to prevent energizing of the heating and ignition coils l8 and II through the relay 2|a after the contact I! has been opened.

The operation is the same as the control diagram of Fig. 4. Upon interruption of the power while the burner is operating the solenoid valve 20 and the relay 2|a drop out and the burner cannot be restarted until the thermal element l6 has cooled to close the contacts I! and Ila.

In Fig. 5a is shown a further modification having a relay 2|b energized through normally closed contacts 2| 0' connected to the contact I! by the thermal element l6. When the relay 2|b is energized it closes contacts 22b in circuit with the solenoid valve and contacts 23b in a holdin circuit 24b. In this modification all of the contacts necessary to secure the time delay between shutting down and restarting of the burner are associated with the relay 2| 2). There is no difference in operation.

' For high combustion rates and stability of the combustion under variationsin the gas pressure, it is important that the combustion start at the fuel injection orifice. If the combustion does not start at this point and a solid jet of unignited or unburning fuel is present in front of the orifice, there is a tendency for the fuel to mix with the air at a localized zone at or in the combustion chamber and burn there with a blue flame and with incomplete combustion. In the Fig. 1 construction this is avoided by extending the fuel injection nozzle 8 axially into the core of the combustion air vortex so that the whirlin combustion air can get in back of the fuel stream and diffuse into the outside of the fuel stream at the nozzle orifice. This provides a combustible mixture at the outer surface of the fuel stream in which combustion can start. The fuel injection nozzle 8 discharges through the opening 8a in the baffle plate 8b partially closing the outer end of the fuel injection chamber 3. Combustion air entersythe annular space between the bafile plate 8b and the fuel chamber 3 and whirls around distribution" during-" burning a ally increases relative'to the outsi uieeutei'mese'spirai adie ht tiie inrir surfac g. surfaCefthe' fuel stiean'ii Q In Fig. 6" the 'fue1 discharge orifice '30" extends axially into the-111613113 cti'n' chamber 31inthe same fnahiier ais nozzle d "p oi'i ided ati'ts; base' witha Vnturi throat 3 viiig eiir inlets 10 The combustion takes mace: with a luminous yellow flame 'varying'to White which stas"; at'tlie" fuel-nozzle outlet; exp'afidy flatly-through the center of thecombus tioh very nearly' the i combustion tube from outlet edge of the orifice 1, The comb'ust completed in a short" lei'igt the combustiohf tubea'ta'heat release theoz df-"off 9005000 B; t. u. perhour pet cubic fo'otf D etcthe*hi'gslri speed rotation ofthe combus'tiofi aithere may be slippage between-the outei an -1nne'1"1'ayei"s of airand the angul ai" Velocity" at thementer which contains th'efuelstfeaih (and the productsof combustion) may be equal to' or-lss-thanthe angular velocity of"the*air adjacent the w'alls of v the combustion tubes" In' effectjthe combustion air" is wrapped-around the'fuel -stfeamwhich ingradually picksup' rotatioifiaf 'spe'ed as-coihbus'tion takes place until-finally-wh'eii combustion isco r nf plete the entife mass has" a more nearly un'iform -.iangular velocity. There is aconti'nual eddying.

This and the .hightemperatures of -co mbustion ,1 make measurementssofthe veloeity I A 30,000 B. t.'u.-perhour burilef has been con-j: .structed with a2 A2 combustioii' -tube; a; scfoll 2 in axial width withanehtrantie s1ot= wide '"1one*), andan aieumet veoc-ityof 41150- feet/minute; In this-the combustion was completed in the firstglO" oi ieng'mer'the combustion tube: Ina"'75,00 0'lB;"t,u. p houifburiier, the combustion tube-was 4" in dia'metr, thescrolf 2 /2 wide, the combustion air ezitre'iiice slot 1 wide/(by 2%" long) and arf a'ii ihltivelocity oi 5,600 feet/minute; In this the cmbustiefi completed" in" 10" of the combustion tubel In suchiburnerathe inlet nozzle 01' eritrahcslt has" a ratio of aXialwidthto -radial thickiies'sgi 'e'ater 50 than 6:1 and the air inlet velocity is of the {order of 20 000 die'et/miriutewhefdis the' diahieter of the combustion tube in feefi' H r 3 Velocity measurements made witlf a Pitot' be: indicatelthe same general p'atter'fi {ofvel' ity ith the g s supply cutoff and only air'supplie to thebui'h'er i Thethighest tangential velocity is' at the" outsi e andr'the lowest tangential velocity' is a he center; Starting with'a maximum at the inle't' iioz'zle; the velocity at the outsidladj aceht the inner su'ria e of; the combustion" air i'chainberi and eombustiori tube) gradualyeide'citeaseswthroughout -the -fco1fi bustion zone: The velocity' "*at tl'i an the" greatest"axial'velocittr' ambit V inn rmo t; spiral" hatrihg'lthe small t; tarieen Velocity and" the smaneewgeu velocity or pitch: At-the 'eginnine of the" combustion zone (aidjaceh't' the combustion air' chamber) the velocitfy airthe outside decreases and the veloc ity atthe enter ihcreas'es' but iselways-iess than the out); side-" elocity; In effctthje elbcity'et the out side s piogiessiveltf trehsrefied to" the inner my; ejrs and megradientor rate of change cf'veloc'itybet een the successive layers decie'ases At my pointthe c'oir 'ibustion 'f zone the velocity "de chases mmup outside toward the cehtje While the velocity of the conce'jntiic spirallayeis' varies throughout the combustion zone, the pitch ofthe -res'15ective1ayersdoes not materially id-combustion: n $61116 ideaof the relative veloeitieSica n be Ob -jtaified from measurements made" with the gas off inthe 2 inch bur'ne'r Atthe beginning of the" combustion tube; thevelocity at the outsidehas: decfe'a-sed from 4 750 ft7niim1te' at "the 'iriiet: nozzleto 3,300 feet/minute; 2% inches do'wnthe: tube thevelocity at the outside is 2,560 feet/min utfJ- 5%=-in'cliesdown the tubeitoward the eiid. ofthe zone -of maximum 'cgihbi'istiofi the velocity at the outside is 2,000 feet/minute. V At thepl'ahe 2% ifibhes ffoiri th'e'begiiihing 0f the combustion: tube, velocitydecreases-toward the cent fastei than the radius becomiir'lg close to zero inch frm the center? Further: dowri the tube; th relatitie' velocity at the cehteris' greater, butin" lhparts'of the combustion-zor'le; theirrilhi' tude is' lessat the ceritef-th'an at the outside.

The velocity 1 distribution; which results froth] the efiort to keep combustion air iri a thi'ii layer adjacent the outside-of the cdr'ribustiotittmh; results in thor'ough and rabid c'oliibusiiioi'iwitha yefj stable'fiafrie." The figures giv'eri show'that the air 'canfibt be-kept iri'this thih layi butth e: air withthe' highest'ijotatiohal afi'd axial veneer is in' this layer 'ar'id the air has" progressively lowe' a'XiaIand rotatioiial telocitie's'towafd the ceht' When a wider i'nl'etj o z'z le" is used} the velocity at: the center inc'iea'ses' and 'the 'combu'stioh is not: as rapid or a s stable." v

Iii Fig; 7 is a modification of'the fuel injectioii; and ignition which may be applied "'to the burriei of Fig. 1.' The plate I511 at the end of thecon'if bustion chamber 2' has an inside diameter slightly less than the diaineteriof the orifice 'i td'bri g the ig'hit'ion' coil clioser'to thefcoi eof thevofte'zi and-thereby obtaihxiioie rapid i'giiitioiil Soloii' sis-t e ighitiodcoil is outside th ebur nihg fuel stream and shielded from the flameby the plate [5a, it'may be close tothe fuel streamrwithout becoming overheated. The 'igh'ition'coil' H is carried on an annular ceramicbase lZahetweezd ailiiular rows Of fQiICIlI Iif If EHtiZ-H y spaced teeth [Z 'band I2c. The'g'as diifuses'into' contact with ignition coil throughth'e "space between the teeth. Ihe baseizaiscarifiedffinan annular re?- cess mem -outer baitofth co i'calfuel m jectid'n chainbei 3211* The"fuelirrjectiorichariibf is fastened to the outside of the plate |a and a sheet of mica l5b' provides electrical insulation between the coil ll'and the plate a. At the apex of the fuel injection chamber is a nozzle 80 which may take the place of the metering orifice in the gas line. Enclosing the rear of the fuel injection chamber is a pressure equalizing chamber 33 having a tangential inlet 34 connected to the gas line 9. The gas swirls around the outside of the-fuel injection chamber and is to some extent preheated. The primary object of the pressure equalizing chamber is to provide a smooth flow of gas into the nozzle 80. This stabilizes the combustion anddecreases streamers of burning as at the end of the combustion zone.

What I claim as new is:

1. In a gas burner, walls defining a combustion air chamber in which there is substantially no combustion, means for supplying substantially all of the combustion air to the chamber in the form of a spiral layer or band having a width substantially equal to the axial length of the combustion air chamber at a velocity such that the greatest part remains adjacent the inner surface of the chamber creating a vortex of greatest tangential velocity at the outside and least at the center and having a pitch substantially equal to the width of the band, a generally coaxial heat transmitting combustion tube in which the combustion takes place leading from one side of the chamber around the axis of the vortex, and a gas injection nozzle projecting into the core of the vortex on the opposite side of the chamber around which air swirls in contact with the nozzle and the gas stream discharged combustion air chamber at a velocity such that I the greatest part remains adjacent the inner surface of the chamber creating a vortex of greatest tangential velocity at the outside and least at the center and having a pitch substantially equal to the Width of the band, a generally coaxial heat transmitting combustion tube in which the combustion takes place coaxial with the vortex leading from one side of the chamber, a wall closing the other side of the chamber, and a gas injection nozzle discharging gas fromthe other side of the chamber toward the combustion tube and positioned so the vortex whirls around and in contact with the nozzle at the rear of the nozzle orifice as regards the direction of gas flow and produces a combustible mixture at the nozzle discharge at which combustion starts.

3. In a gas burner, walls defining a combustion air chamber in which there is substantially no combustion, means for supplying substantially all of the combustion air to the chamber in the form of a spiral layer or band having a width substantially equal to the axial length of the combustion air chamber at a velocity such that the greatest part remains adjacent the inner surface of the chamber creating a vortex of greatest tangential velocity at the ousidte and least at the center, a generally coaxial heat transmitting combustion tube in which the combustion takes place leading from one side of the chamber around the'axis of the vortex, a gas injection nozzlegprojecting'into the core ofthe vortex oh the opposite'side of the chamber around which air swirls in'contact with the nozzle and the gas stream discharged therefrom, and produces a combustibleymixture at the nozzle discharge at which combustion starts, and walls defining an orifice at the entrance tothe combustion tube smaller than the adjacent section of the tube beyond the orifice for producing a turbulence causing the combustion to fill the tube immediately beyond the orifice.

4. In a gas burner, walls defining a combustion air chamber in which there is substantially no combustion", means for supplying substantially all of the combustion air to the chamber in the form of a spiral layer or band having a width substantially equal to the axial length of the combustion air chamber at a-velocity such that the greatest part remains adjacent the inner surface of the chamber creating a vortex of greatest tangential velocity at the outside and least at the center; a generally coaxial heat transmitting combustion tube in which the combustion takes place coaxial with the vortex leading from one side of the chamber, a wall closing the other side of the chamber, a gas injection nozzle discharging through said wall toward the combustion tube at the center of the vortex, and walls defining a restricted throat through which the vortex flows into the tube, the throat being smaller than the combustion tube beyond the throat as regards the direction of flow and the throat producing a turbulence causing the combustion to fill the tube immediately beyond the throat.

5. In a gas burner, walls defining a combustion air chamber, means for supplying substantially all of-the combustion air to the chamber in the form of a spiral layer at a velocity such that the greatest part remains adjacent the inner surface of the chamber creating a vortex of greatest tangential velocity at the outside and least at the center, a generally coaxial combustion tube in which the combustion takes place leading from one side of the chamber around the axis of the vortex, means injecting gas centrally into the opposite side of the chamber, and a thermal flame detector for controlling the burner, said detector being located on the inner peripheral surface of the chamber in contact with the layer of combustion air to receive radiant energy from the fiame.

' 6. In a gas burner, walls defining a combustion air chamber, means for supplying substantially all of the combustion air to the chamber in the form of a spiral layer adjacent the inner surface of the chamber creating a vortex, a generally coaxial combustion tube in which the combustion takes place coaxial with the vortex leading from one side of the'chamber, means injecting gas into the chamber from the other side of the chamber toward the combustion tube, and a thermal flame detector for controlling the burner, said detector being located on the inner peripheral surface of the chamber in contact with;the layer of combustion air to receive radiant energy from the flame.

7. In a gas burner, walls defining a generally cylindrical combustion air chamber in which there is substantially no combustion, means for supplying substantially all of the combustion air tangentially to the chamber in the form of a spiral layer or band through an inlet extending throughout the axial length of the chamber and at a velocity such that the greatest part remains adjacent the inner surface of the chamber creatstream discharged therefrom and produces a combustible mixture at the nozzle discharge at which combustion starts.

8. In a gas burner, walls defining a generally cylindrical combustion air chamber in which there is substantially no combustion, means for supplying substantially all of the combustion air to the chamber in the form of, a spiral layer or hand through an inlet extending throughout the axial length of the chamber and at a velocity such that the greatest part remains adjacent the inner surface of the chamber creating a vortex of greatest tangentialvelocity at the outside and least at the center, a generally coaxial heat transmitting combustion tube in which the combustion takes place coaxial with the vortex leading from one side of the chamber, and walls forming a throat at the entrance to the combustion tube of less diameter than the cham-.

ber causing the air to hub the tube, and a gas injection nozzle projecting into the core of the vortex on the opposite side of the chamber around which air swirls in contact with the nozzle and the gas stream discharged therefrom and produces a combustible mixture at the nozzle discharge at which combustion starts.

9. In a gas burner, walls defining a scroll shaped combustion air chamber, a fiat nozzle for supplying substantially all of the combustion air to the chamber in the form of a spiral layer adjacent the periphery of the walls at a velocity such that the greatest part remains adjacent the inner surface of the chamber creating a vortex of greatest tangential velocity at the outside and least at the center, the nozzle having a ratio of axial width to radial thickness greater than 6:1, means for forcing air through the inlet at a velocity of the order of 20000d feet/minute where d is the diameter of the combustion tube in feet, a generally coaxial combustion tube of less diameter than the chamber in which the combustion takes place leading from one side' of the chamber around the axis of'the vortex, and a gas injection nozzle projecting into the core of the vortex on the opposite side of the chaml0 ber around which air swirls in contact with the nozzle and the gas stream discharged therefrom. 10. In a gas burner, walls defining a scroll shaped combustion air chamber, a flat nozzle for supplying substantially all of the combustion air to the chamber in the form of a spiral layer at a velocity such that the greatest part remains adjacent the inner surface of the chamber creating a vortex of greatest tangential velocity at the outside and least at the center, the nozzle having a ratio of axial width to radial thickness greater than 6:1, means for forcing air through the inlet at a velocity of the order of 2000012 feet/minute where d is the diameter of the combustion tube in feet, a generally coaxial combustion tube in which the combustion takes place coaxial with the vortex leading from one side of the chamber, walls forming a throat at the entrance to the tube of less diameter than the chamber, a wall closing the other side of the chamber, and. a gas injection nozzle discharging gas from the other side of the chamber toward the combustion tube and positioned so the vortex whirls around and in contact with the nozzle at the rear of the nozzle orifice as regards the direction of gas flow.

ROBERT D. SHAP'IER.

REFERENCES CITED The following references are of record in the file of this patent:

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